Power operated slips for rotary machine



Oct. "22, 1957 s. w. LONG 2,810,551

POWER OPERATED SLIPS FOR ROTARY MACHINE Filed May 16, 1950 6 Sheets-Sheet 1 Q F (a. v mm 0 will a Q Q Q 9 E m we 9 g Q m1 F!- q III! FNO III" N n l/IW E INVENTOR.

Spence? 40. zone Oct. 22, 1957 s. w. LONG POWER OPERATED SLIPS FOR ROTARY MACHINE Filed May 16, 1950 6 Sheets-Sheet 2 m w m 5 m x d i l O N u u w .A J n 0h mo l r I. m0 n 5 i 5 Q. M. NP QPM. QC... 1. Q m s p mm mm a i m w I a II; .q u N 1111! CM #MIX mm r\ V \Q A y 1 w. 2 x4 w 5 m m 1 we Q\. I'- m mm b N. 9 3 ov a Q & s

INVENTOR. SPENC'EQ 6U. (0N6 BY M a 84\ ,4770EA/EF5' Oct. 22, 1957 g s. w. LONG 2,810,551

POWER OPERATED SLIPS FOR ROTARY MACHINE INVEN TOR. SPEA/C'EQ (U. (OA/G' HTTUENEVS' Oct'. 22, 1957 s. w. LONG POWER OPERATED SLIPS FOR ROTARY MACHINE Filed May 16, 1950 6 Sheets-Sheet 4 SUPPLV IIES Ill sx/musr 5 R6 mw m W V. mm w M Cf/M m Oct. 22, 1957 s. w. LONG 2,810,551

POWER OPERATED SLIPS FOR ROTARY MACHINE Filed May 16, 1950 e Sheets-Sheet 5 s a/a e (1/. 401m,

- IN V EN TOR.

Oct. 22, 1957 s'. w. LONG 2,810,551

POWER OPERATED SLIPS FOR ROTARY MACHINE Filed May 16, 1950 6 Sheets-Sheet 6 INVEN TOR. SPENCER 6U- LONG POWER OPERATED SLIPS FOR ROTARY MACHINE Spencer W. Lang, lngiewood, Califi, assignor to The Nationai Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Appiication May 16, 1950, Serial No. 162,210

8 Claims. 01. 255-23 This invention relates to the rotary well drilling art and is directed to improvements in pipe handling apparatus. This invention finds particular uusefulness in connection with a power operated slip assembly for supporting drill pipe on the rotary machine as employed in the drilling of wells.

Rotary machines of commercially available types serve to rotate the drill string while the bit is on bottom and to provide means for coupling and uncoupling the sectional drill string when it is necessary to replace the bit. Rotary machines are commonly provided with master bushings which define a tapered bowl to receive wedgeshaped siips. When the slips are seated within the bowl they cooperate to support the lower portion of the drill string so that an upper section or sections can be threadedly connected or disconnected as desired. Ordinarily the slips are manually positioned and withdrawn to and from operative position within the slip bowl. Since the weight of the slips is relatively great the manual effort involved in lowering and raising them repeatedly is considerable. Various devices have been proposed to raise and lower these pipe handling slips by power in order to avoid fatigue on the part of the members of the drilling crew, and these devices commonly have involved power cylinder assemblies mounted on the derrick floor and spaced from the rotary machine and carrying a laterally extending arm for raising and lowering pipe slips with respect to the slip bowl. Such devices are cumbersome and interfere with normal use of the floor area for conventional operations in drilling a well by the rotary method. Furthermore, such devices necessarily operate to raise and lower an ofi-center load since the weight of the slip bodies and attendant mechanism are positioned centrally of the rotary machine, whereas the power operating mechanism is disposed on the derrick floor at one side of the rotary machine.

It is the principal object of my invention to avoid these shortcomings in power operated slip mechanisms and to provide a superior device for raising and lowering the slips with respect to the slip bowl provided on a rotary machine.

Another object is to provide a power lift mechanism which is entirely enclosed within the rotary machine itself so that floor area needed for conventional well drilling operations remains clear and unobstructed.

A more detailed object is to provide such a device incorporating a power lift apparatus below the bearings of the rotary table which operates to raise and lower pipe slips between an operative pipe supporting position within the master bushing slip bowl, and an elevated inoperative position.

A related object is to provide a device of this type having parallel posts which slide in bearings provided within the rotary table itself and which rotate with the table.

Another object is to provide a quick detachable connection at the upper ends of such posts so that the pipe supporting slips may be removed when desired and so that a substantially projection-free surface for the upper portion of the table in the absence of said slips is also provided.

Another object is to provide a device of this type in which the posts are connected to each other only at their bottom ends so that no interference is developed with respect to the Kelly-drive bushing.

Another object is to provide a fluid operated power lift device of improved type which prevents accidental seating of the slips should failure in the fluid supply lines take place.

Other and more detailed objects and advantages will appear more fully hereinafter.

In the drawings:

Figure 1 is a top plan view showing a preferred embodiment of my invention as incorporated into a well drilling rotary machine.

Figure 2 is a sectional elevation taken substantially on the lines 2-2 as shown in Figure 1.

Figure 3 is a sectional plan view taken substantially on the lines 33 as shown in Figure 2.

Figure 4 is a sectional elevation partly broken away showing one of the pipe supporting slips in raised inoperative position.

Figure 5 is a sectional detail lines 55 as shown in Figure 3.

Figure 6 is an enlarged View of the quick detachable connection employed between the upper end of each of the posts and the bracket for each of the pipe supporting slips.

Figure 7 is a schematic diagram partly in section showing the connections for the fluid pressure operated lift device.

Figure 8 is a perspective view of the master bushing assembly used in connection with my invention.

Figure 9 is a side elevation partly broken away showing the Kelly-drive bushing in operative position with respect to the master bushing assembly.

Figure 10 is an end elevation taken substantially on the lines 1li0 as shown in Figure 2.

Figure 11 is a fragmentary detail partly in section showing the mounting of one of the yoke rollers.

Figure 12 is a view similar to Figure 7 showing modified control connections for the fluid pressure operated lift device.

Figure 13 is a longitudinal sectional view of the fourway control valve shown in Figure 12.

Briefly stated, my invention contemplates the provision of power lift means for raising and lowering pipe-engaging wedge slips 10 with respect to a taper slip bowl 11 provided on a master bushing assembly 12. The master bushing assembly is carried by the table 13 of a rotary machine generally designated 14. The power lift means may comprise a plurality of upright parallel posts 15 each mounted for vertical movement within spaced slide bearings 16 provided on the table 13. A quick detachable coupling generally designated 17 connects the upper end of each post 15 to a bracket 13, and a link 19 pivotally connects each bracket to one of the pipeengaging slips 10. A lift ring 20 is connected to the lower ends of each of the posts 15 so that when the ring is lifted by power the posts slide upwardly through the spaced bearings 16 to lift the slips it) out of the slip bowl 11. Figure 4- shows one of the slips 1!) in its raised inoperative position, retracted radially from the drill pipe 21 which extends through the rotary table and master bushing assembly. When the ring 20 is moved downwardly under power the posts 15 descend in unison and cause the slips It) to move into operative position within the slip bowl 11 to support drill pipe 21.

More particularly, the rotary machine 14 includes a base structure 22 supported on a sub-base 22a and contaken substantially on the nected thereto by means of bolted connections 2212. A stationary guard'64 on the base encircles the upper portion of the table 13. A main bearing assembly 23 rotata ly' upp s e able -3 on e ba e 22. and an up thrust bearing assembly prevents upward movement of the table 13 relative to the base 22. The upthrust bearing assembly 24 includes a race ring 25 secured to the table 13 by means of bolted connections 26. The table 13 is provided with the usual ring gear 27 which is driven by the pinion 28 fixed on the inner end of the pinion shaft 29. This pinion shaft is rotatably supported in axially spaced bearings 30 and 31 carried on the lateral extension 32 of the base 22. The pinion shaft 29 extends laterally beyond the end of the base 22 and driven by a sprocket or other suitable means (not shown) The usual locking ring 33 may be fixed to the pinion shaft between the bearings 30 and 31 and cooperates with pivoted pawls 175 and 176 for arresting rotation of thepinio n shaft in either or both directions when desired. The pawl 175 is directly actuated by means of the rod 177 and the pawl 176 is indirectly actuated by means of the link 178, crank 179 and rod 180.

v The table 13 or first table member is providel with a central cylindrical opening 34 and a plurality of offset recesses 35 its upper portion. The second table member or master bushing assembly 12 shown clearly in Figure 8 is formed of two mating halves 36 and 3'7 which cooperate t c define a cylindrical outer portion 38 which is received within the cylindrical opening 34 in the table 13. The bushing assembly 12 is also provided with a plurality of radially extending drive lugs 39 which are received in driving relationship by the oflset openings 35 in the table 13. As shown in the drawings, three drive lugs 39 are provided, two on one of the bushing halves and one on the other. The master bushing assembly 12 is also provided with inclined guideways 40 at its upper end which receive the lower ends of the slips 10 when they are elevated to a retracted inoperative position. As shown in Figure 4, the lower portion 41 of the slips 10 may be bevelled to correspond to the inclination of the su de a s Each of the pipe-engaging slips 119 may be provided with hardened wicker inserts 42 for engagement with the outer surface of the drill pipe. A pivot pin 43 connects each of the slips it! to its respective link 19, and a similar pivot pin 44 connects the link to its respective bracket 18. The quick detachable coupling 17 for connecting each bracket 18 to its respective post 15 is shown in detail in Figure 6. The bracket is provided with a downwardly facing socket 45 which receives a projection 46 on the upper end of the post 15. The lower annular surface 47 of the bracket 18 rests on the flange 48 formed integrally with the post 15. The flange 48 is slotted at 49 to receive downwardly projecting keys 50 provided on the bracket 18. The engagement between the keys 50 and the slots 49 prevent relative rotary movement between the bracket 18 and the post 15.

A threaded bushing 51 is fixed within a threaded recess provided on the extreme upper end of the post 15, and a bolt 52 is threadedly received within the threaded bushing 51. The bolt 52 extends through a vertical bore 53 provided in the bracket 18;, and the bolt head 54 engages the annular shoulder 55. A noncircular socket 56 may be provided in the upper end of the bolt to receive a suitable wrench (not shown). When it is desired to disconnect the brackets 18 from the posts 15 the bolts 52 are turned to release the threaded connection between the bolts 52 and the threaded bushings 51. The brackets 18 may then be raised vertically to lift the sockets 45 upwardly away from the pro ections 16 on the posts 15. For convenience in lifting the brackets 18 together with links 19 and slips 10, hand grips 57 and 58 are proi sd on e c Qt he br kets 1 The provision of the threaded bushings 51 allows the 4 make-and-break connection to be accomplished on the mating threads 59 so that the threads which are formed in the upper ends of the posts 15 are not subjected to this wear. A cap screw 60 on the bracket 18 projects into an annular groove 61 provided on the bolt 52 so that disassembly of the bolt 52 with respect to the bracket 18 is prevented even when the bracket 18 is removed from the upperend of its respective post 15. When the brackets 18 are removed from the posts 15 the extreme upper ends 62 of the bushings 51 lie below the upper surface 63 of the master bushing assembly 12 when the posts 15 are held in their lowest position. This is an advantageous feature for it avoids interference between the upper ends or the posts 15 and the Kelly-drive bushing 66 when the latter is in place for driving the kelly 65.

When the brackets 18 and their respective links 19 and slips 10 are removed they may be positioned at any desirable location on the derrick floor (not shown). The kel y 65 is cons n ed t the d ill P pe and lowered in operative position as will be understood by those skilled in the art. The Kelly-drive bushing assembly generally designated 66; may be provided with driving rollers 67 for contact with the kelly. The assembly 66 rests on the pper end of the-master bushing assembly 12 and is provided with drive lugs 68. which are received within the upper ends of the offset recesses 35 which are provided onthe table 13. The Kelly-drive bushing 66 thus rests on the master bushing assembly 12 and is driven directly from the table 13. If desired, a pilot sleeve 69 may be provided on the Kelly-drive bushing assembly 66. The lower end 70 of this pilot slides down the taper slip bowl 11 to align the bushing 66 and kelly 65 axially of the rotary table 13 prior to engagement of the drive lugs 68 with the ofiset openings 35. The construction and operation of this pilot is, set forth in detail in the Young Eatent 2,422,383, granted lune 17, 1947.

The lifting ring 20 is provided with a plurality of taper sockets 7-1 for reception of the lower taper end 72 on each of the posts 15' A nut 73 threaded to the lower end of each post 15 anchors the taper portion 72 within the taper socket 71- in the lift ring 20. A: rigid connection between each of the posts 15 and the lift ring 20.is thus provi ed. A key. 7.4 may. be, provided to align each post 15 with respect to its respective socket 71 on the ring; 20.

Since the posts 15 are carried in bearings 16; on the. table 13 they will rotate with the table as a unit and carry the ring 29 with them. Means are provided for raising and lowering the rotary ring 20, and as shown in. the drawings this. means includes a yokeassembly generally designated 75, This. yoke assembly includes a pair of arms 7.6, and 77. each fixed to an end of the sleeve; 170. Keys171- prevent,- relative rotation of the arms with respect to the sleeve; and a central key 172 connects, thesleeve to the. rockshaft 78. The sleeve is carried in suitable bearings. 7.9 provided on the sub-base 22a. The rockshaft is supported at one end within the sleeve 1-70 and at the other end by a suitable bearing 173'. The

torque applied by the rockshaft 78 to the sleeve 170,-

causes the arms 76 and 77- to move in unison andwithout danger that onearm should lead the other.

The swinging end of each of the arms 76 and 7,7 is

provided with an integral socket 80- a bearing housing 80a for rotatably supporting a roller shaft 8 1. Axially spaced bearings 174 support the roller shaft 81 within the housing 80a. The shaft projects radially inwardlyfrom the bearing housing 80a and is provided with a roller 82 which is positioned. between the upper andv lower flanges 83 and 84 respectively of the lift ring 20. The rollersSZ, are thus positioned within the groove 85' defined between theupper and. lower flanges 83 and 84.

The yoke assembly 75 is ordinarily used to raise and lowerthe liftring 20 only when the latter is not rotating, since the slips 10 are normally moved from operative to inoperativeposition, and vice versa, only'when the table 13- is at rest. However, the rollers 82 0f the yoke assembly 75 can function to raise or lower the ring 20 regardless of its angular position with respect to the base 22 of the rotary machine 14. The force applied by the rollers 82 to the ring is always an axially directed force because the sleeve and yoke construction insures that the same lifting force is applied by each of the arms 76 and 77.

Power operated means are provided for oscillating the rock shaft 78 when desired, and as shown in the drawings this means includes a crank 86 fixed on the rock shaft and connected by a pivot pin 87 to a clevis 88. The clevis 88 is carried on the projecting end of a piston rod 89 extending from a power cylinder assembly generally designated 90. This assembly includes a piston 91 fixed on the piston rod 89 and arranged to reciprocate within a cylinder 92. One end of this cylinder is pivotally connected by means of pivot pin 94 to an ear 93 fixed on the subbase 22a. The piston 91 divides the interior of the cylinder 92 into a front chamber 95 and a rear chamber 96. Pressure fluid may be admitted into either of the chambers so that the piston 91 may move the ring 20 positively in either direction.

Means are provided for cushioning the stroke of the piston 91 and rod 89 to prevent impact of the piston against the ends of the cylinder. This means may include bypass ports 97 and 98 having a needle valve 99 adapted to restrict the flow of pressure fluid through the ports. When the piston approaches either end of the cylinder,

pressure fluid is forced through the restriction provided at relatively high velocity, thereby providing a dashpot effect. Each end of the cylinder may also be provided with a spring urged check valve 100 which permits flow through the bypass ports 101 and 102 only in one direction. These check valves open when the piston 91 initially moves away from the end of the cylinder in which the check valve is mounted so that the main body of pressure fluid need not pass through the restriction of the needle valve 99. In accordance with my invention, means are provided for constantly supplying pressure fluid to the rear chamber 96 so that the piston 91 and rod 89 are always subjected to a force tending to raise the slips 10. When it is desired to lower the slips 10, fluid under higher pressure intensity is admitted into the front chamber 95 to overbalance the pressure existing in the rear chamber 96. The force then applied to the piston 91 results from the differential pressure in the chambers 95 and 96. The higher pressure in the front chamber 95 overbalances the lower pressure in the rear chamber 96 so that the piston 91 and rod 89 are moved in a direction to seat the slips 10. Release of pressure in the front chamber 95 again allows the existing pressure in rear chamber 96 to move the piston 91 and rod 89 forward.

The purpose of this arrangement is to prevent accidental setting of the slips within the taper bowl 11. Serious consequences would result if the slips 10 should be lowered into seating position within the slip bowl while the drill pipe 21 was being lowered into the hole. i provide a pressure regulator 110 of the general type shown in the Lynn et al. patent, No. 2,042,112, which is equipped with an inlet 103, an outlet 104 and an exhaust opening 105. Pressure fluid supplied to the inlet via piping 106 causes pressure to be maintained on the pipe 107 at a constant value, depending on the setting of the adjusting screw 108. Thus, for example, if air pressure at approximately 100 p. s. i. is supplied through the piping 106, the adjusting screw 108 can be set so that a relatively constant pressure of 60 p. s. i. is maintained in the connecting line 107. A check valve 109 prevents return flow of fluid pressure from the pressure regulator 110. The check valve 109 and pressure regulator 110 are both mounted on the power cylinder assembly 90 so that failure of the piping and fittings in the lines 106 and 107 is unlikely.

A pressure line 111 extends from the check valve 109 to a remote location near the drillers position to a fourway valve 112. A pressure supply line 113 also connects to the four-way valve 112. Another line 114 leads from the four-way valve to the port 121 on the power cylinder assembly 90. The four-way valve 112 is conventional in design and operation and its particular construction forms no part of the present invention.

In operation, pressure fluid, preferably air, is supplied through the shut-off cock 122 and supply line 113 to the four-way valve 112. If the driller actuates the foot pedal 123 marked D, pressure is supplied through line 114 to the front chamber through port 121. Assuming that p. s. i. is supplied through the line 114, the piston 91 moves rearward within the cylinder 92 because the pressure in the rear chamber 96 is regulated at a lesser value, for example, 60 p. s. i. As the piston 91 moves rearwardly, the slight increase in pressure in the chamber 96 causes the pressure regulator to open partially the exhaust port 105 so that pressure in the line 107 and rear chamber 96 remains substantially at 60 p. s. i. The piston 91 continues its rearward movement until the slips 10 are positively seated within the bowl 11 in pipe-supporting position. When the driller actuates the foot pedal 124 labelled U, the four-way valve 112 connects eX- haust port 125 and line 114 so that pressure in the front chamber 95 and line 114 is bled to atmosphere. At the same time fluid pressure is applied to line 111, check valve 109, piping 106 and to the inlet 103 of the pressure regulator 110. Assuming a pressure of 100 p. s. i. in the line 106, the pressure regulator supplies pressure to the line 107 and rear chamber 96 at a regulated value of substantially 60 p. s. i. The exhaust port 105 remains closed. Since the rear chamber 96 is pressurized at 60 p. s. i., and since the front chamber 95 is bled to atmosphere, the piston 91 and rod 89 move forward to raise the slips 10. From this description it will be understood that a constant force is applied to the piston 91 and rod 89 in a direction to raise the slips 10, and that in order to lower the slips a greater force is applied to the piston 91, overbalancing the constant force, causing the piston 91 to move rearwardly within the cylinder 92.

It will be observed that raising of the slips 10 serves automatically to retract them radially from the pipe 2.1 because the slips 10 gravitate outward to lie directly below the supporting pivot pins 44 when they are in raised position. This is an advantageous feature because it provides adequate clearance for passage of tool joints, protector collars, etc. on the pipe without danger of interference.

After the pipe has been lowered into the hole section by section and drilling operations are to commence, the bolts 52 are unthreaded so that the brackets 18, links 19 and slips 10 can be withdrawn and set aside. The posts 15 are then moved downward so that they do not present any projections above the upper surface 63 of the table 13 or the stationary table guard 64. The kelly 65 and its drive bushing may then be lowered into operative position as shown in Figure 9.

In the modified form of my invention shown in Figures 12 and 13, the control system for operating the piston 91 within the cylinder 92 employs a four-way pilot valve assembly 130. The assembly is positioned close to the power cylinder assembly 90 and may be supported on the cylinder 92 by means of a suitable bracket 131. Piping 132 connects the pilot valve assembly 130 to one end of the power cylinder assembly 90, and piping 133 connects the assembly 130 to the other end of the power cylinder assembly 90. Fluid under pressure, preferably air, is supplied through line 134 to the assembly 130 via the check valve 135. The check valve 135 prevents return flow through the line 134.

As shown in Figure 13 the four-way pilot valve 130 may comprise a housing 136 having an axially movable valve element 137. This valve element is connected to pistons 138 and 139 at its opposite ends which operate in cylinders 140 and 141 respectively fixed to the housing 136. These pistons and their respective cylinders comprise a preferred means for shifting the position of the valve element 137, but it is recognized that the element 137 could be shifted by any other means as desired. When air pressure is supplied through the control line 142 the piston 139 moves the valve element 137 to the position shown in Figure 13. In this position, air pressure admitted through the check valve 135 enters the central chamber 143 and passes through ports 144 into the bore 145 in the valve element 137. The air under pressure then passes out through ports 146 into the chamber 147 and into the piping 133. This causes the piston 91 to move in a direction to extend the piston rod 89 and to raise the slips 1!). Air in the forward chamber 95 is exhausted through the piping 132 and into the chamber 147a. The exhausting air passes inwardlythroug'h ports 148' into the bore 149 in the valve element 137. The exhaust air then passes outward through ports 150 into the chamber 151 and out through the exhaust nozzle 152 to atmosphere.

In a similar manner, when air pressure from the control line 153 acts on the piston. 138' to shift the valve element 13.7 away from the position shown in Figure 13, air pressure admitted through the check valve 135 passes through ports 148, bore 149 and ports 150 to reach piping 132. This pressurizes the forward chamber 95 and causes the piston 91' to retract the rod 89 to set the slips 10. Simultaueously, air in the rearward chamber 96 is exhausted through piping 133, ports 14'4', bore 145 and ports 146 to the exhaust nozzle 154. It Will be observed from a consideration of Figure l3v that the valve element 137 is pressure balanced so that the fluid pressure entering the housing from the check valve 134 does not tend to move the valve element 137 in one direction or the other.

In this form of'my invention air under pressure is admitted to the T-fitting 155. The control line 153 is pressurized' when the D pedal 123 is depressed, while the control line 142 is bled to atmosphere through the port 125. Similarly, when the U pedal 124 is depressed, the control line 142 is pressurizedwhile the control line 153 is vented. to atmosphere through port 125. The four-way control valve 112' is ordinarily located at the drillers position some distance away from the rotary machine. Therefore, the control lines 1427 and 153; as wellas the pressure supply line 134, conveniently takes the form of flexible hoses.

Should one ofthe hose lines 134, 142 or 153 fail in service the slips 16 remain in the position that they occupied when the failure'occurred' and are neither raised nor loweredby such failure. Thus, failure ,of the hose line 134- prevents raising or lowering of the slips under power, regardless ofthe position of the valve element 137 in thefour-way pilot valve assembly 130. Should one of the pressure control lines 142 or- 153 fail in service, the valve element 137 in thepilot valve assembly 130 remains at its'previous position-so that air supplied'through the check valve 135 does not change theposition of the slipsbut serves to maintain them in such position. The slips 10-are therefore prevented from being seated inadvertently while drill pipe is being lowered intothe well hole, and similarly, inadvertent raising of the-slips is also prevented.

A safety device may be incorporated-into this pressure operated control system, and asshoW-n in the drawings this may comprise a shut-oft cock 156 interposed in the air supply line 157. The handle 158 of theshut-ott' cock may belowered tothe full line position to permit-operation of the slips while the drill pipe is beingwithdrawn or reinserted into the well hole. When drilling operations are commenced, with the drill stem bushing'ofi-in the position shown in Figure 9, the handle 158'is swung manually to the dotted linepositionshown in-Figu-re-l0 so that the slip actuating mechanism= cannot beinadvertently raised during drilling-- operations.

Having fully described my invention, it is to be under- 8 steed that I do not wish to be limited to the details herein set term, but my invention is of the full scope of the appended claims.

I claini:

1.- In a rotary machine having a base, a table assembly retambly mounted upon the base and provided with a downwardly converging taper bore, a post mounted for vertical sliding movement on the table, and a pipe-supporting slip received within the taper bore, the improvement comprising: means for connecting the slip to the upper end of said post, said means including a first threaded element extending axially of the post and fixed relative thereto, a bracket having a socket to receive a portion of the upper end of the post, tongue and groove alignment nieans holding the bracket and post in predetermined angular relationship, the bracket having a bore extending axially of the" post, and a second threaded elenrnt extending through the bore for engagement with the first threaded element andengaging a portion of the bracket to removably secure the bracket on the post.

2. In a rotary machine having a base,- a table assembly rotatably mounted upon the base and provided with a downwardly converging taper bore, a post mounted for vertical sliding movement on the table, and a pipe-supporting slip received Within the taper bore, the improvement comprising; means for connecting the slip to the upper end ot'said post, said means including an internally threaded nut element extending. axially of the post and listed relative thereto;- a Bracket having a socket to re ceive at portion ofthe upper end of the post, tongue and groove alignment meansholding the bracket and post in predetermined angular relationship, the bracket havrug-s bore extending axially of the post", and an externally threaded bolt element" extending through the bore for engagement with the said not element and engaging a portion. of the bracket to removably secure the bracket on the post;

3. l'n a' rotary machine having a base, a table assembly rotatablymouhted' upon the base and provided with a downwardly converging taper bore, a post member mounted for vertical sliding movement on the table, and a pipe-supporting slip received within the taper bore, the improvement comprising: means for connecting the slip to the upper end of'said en member, saidmeans includingla first threaded elementextending axially of the post member and fixed relativethereto; a bracket member, one or the said members having a socket to receive a portion of the other member in telescopic relation, tongue and groovealignment means holding the members in predetermined angular relationship, the bracket member haw ing abore extending axially of the post member, and a second threadethelement extending through the bore for ehgagerrieiiflwith the first threa'ded'element and engaging a portion of th'ejbr aclet' member to removably secure the bracket member on' the post member.

4 1h a pipehan'dling device employing a double-acting fluid pressure cylinder ass'e'mb'l'y'for' raising and lowering pipe-supportingslips relative to=a'-slip'bowl, the combination; of a four-way pilot valve mounted adjacent the cylinder ass'eiriblyand connected the retoby piping" connections; the pilot'valve'having a movable valve element 'shiftahl from a first position corresponding to raising of the slips" to a second position corresponding to lowering. of. the.slips,- a supply line for supplying fluid'under pressure to the pilot valve, a check valve interposed in saidline adjacent the pilot-valve-for preventing return flowof pressure' fluid from 'the pilot valve, and means for ,actuatingithe-pilot: valve to control action of the 'doubleacting fluid pressure cylinder assembly, said means includingi pressure-responsive members opferatively connectedito'smd m'ovab'leivalve eleme'nt, .a control valve positioned remotely from said pilot valve, and separatepi'es Sm rties exteiidingjfifom the control valve to said pressure-responsive members; wher'eby selective pressu'rizing of said lines by the control valve may elfect shifting of the movable valve element.

5. A rotary machine for a well drilling rig adapted to turn a sectional drill string and to support it during coupling and uncoupling operations, comprising in combination: a base, a table assembly rotatably mounted on the base and having a central downwardly converging taper bore, a plurality of pipe-supporting slips received within the taper bore, a plurality of longitudinally movable parallel posts extending through the assembly, linkage means connecting the upper end of each post with one of said slips, a rotary lift ring positioned below the table means fixing each of the posts to the lift ring to assure equal movement of the posts, power means on the base for actuating the lift ring to move the posts longitudinally, said means including a rock shaft on the base, a sleeve rotatably mounted on the base, arms secured to the ends of the sleeve and having roller elements engaging the ring, key means for connecting the rock shaft to the sleeve at a location substantially midway between the ends thereof, and power means for turning the rock shaft.

6. In a pipe handling device having a plurality of pipe-supporting slips received in a taper bowl, the combination of: means for raising and lowering the slips in the taper bowl, said means including a reciprocable element movable by fluid pressure, first pressure means for subjecting one side of said reciprocable element to a relatively high maximum pressure acting to move the reciprocable element in a direction to lower the slips into the taper bowl, second pressure means for subjecting the other side of the element to a lower pressure, and means including a valve for energizing and deenergizing the first pressure means, said second pressure means acting upon de-energizing of the first pressure means to move the reciprocable element in a direction to raise the slips relative to the taper bowl.

7. In a pipe handling device having a plurality of pipe-supporting slips received in a taper bowl, the combination of: a reciprocable element movable by fluid pressure, means including mechanical linkage whereby movement of said reciprocable element serves to raise and lower said slips relative to said taper bowl, first pressure means for subjecting one side of said element to a relatively high maximum pressure acting to move the element in a direction to move the slips into the taper bowl, second pressure means for subjecting the other side of the element to a substantially constant lower pressure, and means including a valve for energizing or de-energizing the first pressure means.

8. A rotary machine for a well drilling rig adapted to turn a sectional drill string and to support it during coupling and uncoupling operations, comprising in combination: a base, a table assembly rotatably mounted on the base and comprising a first member having a central opening, a second member axially insertable into the opening to rest on the first member, the second member having a central downwardly converging taper bore, a plurality of pipe-supporting slips received within the taper bore, a plurality of longitudinally movable parallel posts extending through the first table member, bearing means on the first table member guiding the posts for simultaneous vertical sliding movement, a common lift member positioned below both table members for raising the posts as a unit, means rigidly fixing each post to said lift member, a bracket removably connected to the upper end of each post, and a link pivotally connecting each bracket to one of said pipe-supporting slips, respectively, and providing for lateral bodily movement of the slips relative to the bore, as the posts are raised.

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